This invention relates to a cover apparatus for a deep oil cooker having a sealed cover for high pressure operation and particularly to such a cover for rapid and safe closure and opening of the cooker.
Deep oil cookers are widely used by restaurants for cooking chicken, fish and other foods by immersion in hot cooking oil. Certain restaurants specialize in such foods, particularly deep cooked chicken. In addition to the conventional restaurant where the food is consumed on the presmies, various restaurants and other food retail outlets have a substantial food carry-out business including chicken. In those restaurants and other outlets having large sales volume of cooked foods, a rapid and efficient cooker is essential in order to produce quality products at a reasonable and profitable cost.
The pressure cooking apparatus includes a large kettle or pot having a releasably attached high pressure cover. The pot is filled with cooked oil to a level in spaced relation to the cover. A heating unit is immersed in the oil or an encircling coil unit is coupled to the pot to increase the temperature of the oil to the desired cooking level. The chicken parts are held in a suitable basket and immersed in the oil with the cover closed for deep cooking for a selected period.
The copending application of the inventor filed herewith and entitled "Deep Oil Cooking Apparatus", discloses a particularly satisfactory pressure cooker particularly for cooking food such as chicken.
The cover structure is releasably latched to the pot to seal the pot and create a pressure cooker for the rapid and thorough cooking of the product, and is manually opened and the product removed. The hot oil and vapors created during the cooking cycle present a potentially dangerous condition of the end of the cooking cycle.
In use, the high pressure cooker requires release of the pressure within the cooker prior to removal of the cover. The system should therefore be constructed with some means to release the pressure and establish a safe condition at the end of the cycle, and thereby permit safe cover removal for removable of the cooked chicken. Generally, a manual or automatic pressure release means is provided to release the pressure.
The prior art has further suggested various covers having a mechanical interlock mechanism which incorporates a pressure release unit to prevent opening of the cover with cooking pressure in place. Care is still required by the operator in the event a residual pressure condition exists in the pot notwithstanding operation of the pressure relief means and the interlock mechanism. The efficiency of the cycling is also directly related to the ease of removing the cover for access to the cooker pot.
A releasable cover having a safety interlock is shown in U.S. Pat. No. 3,976,218 which issued Aug. 24, 1976. A cover member rests on the top of a cooking pot. A pivoted arm is secured to one side of the square pot and extends over through a channel formed in the cover. A releasable latch on the opposite side secures the bar to the opposite side of the pot. A threaded shaft is threaded through the bar and is rotated into bearing engagement with the cover to establish a fluid type seal. A diaphram is secured overlying the inner face of the cover. A spring loaded pin is possitively moved by the diaphram above the exterior of the cover in response to pressures within the pot. The rotating shaft is provided with a rotating radially notched plate. When the cover is tightened to the closed position, a notch is aligned with the pin opening. Thus with pressure in the pot, the pin moves outwardly into a locking location. A similar combined pressure interlock is shown in U.S. Pat. No. 4,299,331 which issued Nov. 10, 1981. In the latter patent, the cover has a sealing edge located inside a specially formed rim on the pot. A clamping bar spans the pot with the opposite ends coupled to the outer rim portion. A pivoting cam on the bar to expand the cover into the interior sealing engagement. The cam has a lug aligned with a vertical pin member slidably mounted in the cover. The pressure in the cooking kettle forces the pin outwardly into an aperature in the lug to produce an interlock.
U.S. Pat. No. 2,917,200 which issued Dec. 15, 1959 discloses the cooking kettle having a heavy cover structure mounted in a hydraulically actuated vertical positioning yoke assembly. A positioning cam unit is mounted between the yoke and the cover for positively lowering and lifting of the cover. The cover has a pressure responsive pin in the central portion thereof. The cam is provided with a slot in the cam surface. In the closed cover position, the slot is aligned with the pin. The pressure in the pot again moves the pin outwardly into the cam slot to possitively lock the unit into a locked position Other pot closures systems are shown in various other U.S. patents including the following which have been particularly considered in preparation of this disclosure.
______________________________________ PATENT NO. INVENTOR ISSUED DATE ______________________________________ 1,208,041 Steere 12/12/16 1,821,726 Saporta 11/22/29 2,778,736 Wagner 01/22/57 3,964,637 Luebke 06/22/76 4,103,801 Walker 08/01/78 4,307,818 Singh 12/29/81 4,325,491 Barnhill 04/20/82 4,347,833 Luebke 07/07/82 4,362,148 Luebke 12/07/82 4,485,936 Pardo 12/04/84 4,498,695 Pardo 02/12/85 4,541,543 Elexpuru 09/17/85 ______________________________________
The prior art cover structures generally involve relatively complicated structures or other structures which are difficult to apply and use in a commercial restaurant and institutions, and the like where relatively high volume production is required. Further, the units do not generlly anticipate protection against any residule relatively low pressures which may exist within the pot even after operation of the normal release pressure systems.
There is therefore a continuing demand for an improved cover structure which can operate under the high pressures required for deep cooking and which of course has the necessary long life required by commercial application. The cover unit of course must provide maximum safety and anticipate the less than perfect operation of the normal pressure release systems.
Although various deep cooking pot units are used in the industry, there is a continuing need for a more efficient and effective batch cooking pot-type apparatus and particularly a cover apparatus which is simple in structure and includes means permitting safe and reliable opening of the cooker.